Intensity of muscular system growth in purebred and crossbred steers depending on functional loads

Abstract

The intensity of muscular system growth is largely determined by functional loads on it, and the frequency of growth and development of muscular system is associated with successive differentiations and is largely due to age-related changes in the level of sex steroids. Since crossbreeding is one of the effective methods of expanding the slaughter contingent of cattle the study of the intensity of muscular system growth of carcasses in purebred and crossbred animals is relevant and has indisputable practical application. The results of researches devoted to the study of the influence of functional loads on the intensity of growth and development of muscular system in steers of Blackand-White breed and its hybrids with Aberdeen-Angus and Charolais have been presented in the article. Muscle mass of carcasses was the biggest in Charolais crossbreds at the age of 12, 15 and 18 months it was, respectively, 172,4; 213,8 and 253,6 kg, which is significantly more than in herdmates of the maternal breed and Aberdeen-Angus crossbreds. The periodicity of muscular system development in the anatomical parts of carcasses has been found that largely due to functional loads as a result of which there is a redistribution of the muscular component in them. The biggest intensity of growth is typical for the muscle mass of the abdominal part, the least-for the muscles of the forearm and lower leg. A quarter of all muscles of carcasses accounted for the thigh in which the largest and most valuable in the nutrient framework are the biceps, quadriceps, semimembranosus, semitendinous muscles. The relative weight of the muscles located in the anatomical regions of the axial part of the skeleton with the age of animals has being increased and the muscles of the peripheral part of the skeleton-naturally has being decreased.